Borobudur, also transcribed Barabudur (Indonesian: Candi Borobudur, Javanese: ꦕꦤ꧀ꦝꦶꦧꦫꦧꦸꦝꦸꦂ, romanized: Candhi Barabudhur), is a 9th-century Mahayana Buddhist temple in Magelang Regency, near the city of Magelang and the town of Muntilan, in Central Java, Indonesia.

Constructed of gray andesite-like stone, the temple consists of nine stacked platforms, six square and three circular, topped by a central dome. It is decorated with 2,672 relief panels and originally 504 Buddha statues. The central dome is surrounded by 72 Buddha statues, each seated inside a perforated stupa. The monument guides pilgrims through an extensive system of stairways and corridors with 1,460 narrative relief panels on the walls and the balustrades. Borobudur has one of the world's most extensive collections of Buddhist reliefs.

Built during the reign of the Sailendra Dynasty, the temple design follows Javanese Buddhist architecture, which blends the Indonesian indigenous tradition of ancestor worship and the Buddhist concept of attaining nirvāṇa. The monument is a shrine to the Buddha and a place for Buddhist pilgrimage. Evidence suggests that Borobudur was constructed in the 8th century and subsequently abandoned following the 14th-century decline of Hindu kingdoms in Java and the Javanese conversion to Islam. Worldwide knowledge of its existence was sparked in 1814 by Sir Thomas Stamford Raffles, then the British ruler of Java, who was advised of its location by native Indonesians. Borobudur has since been preserved through several restorations. The largest restoration project was completed in 1983 by the Indonesian government and UNESCO, followed by the monument's listing as a UNESCO World Heritage Site.

Borobudur is the largest Buddhist temple in the world, and ranks with Bagan in Myanmar and Angkor Wat in Cambodia as one of the great archeological sites of Southeast Asia. Borobudur remains popular for pilgrimage, with Buddhists in Indonesia celebrating Vesak Day at the monument. Among Indonesia's tourist attractions, Borobudur is the most-visited monument.

In Indonesian, ancient temples are referred to as candi; thus locals refer to "Borobudur Temple" as Candi Borobudur. The term candi also loosely describes ancient structures, for example, gates and baths. The origins of name Borobudur, is derived from Boro for big and Budur for Buddha. Dutch scholar J. L. Moens says the court poet Mpu Prapanca referred to a holy sanctuary at "Budur" in 1365. Stamford Raffles mentioned "Bóro Bódo" and described the temple in his 1817 book on Javan history. In a footnote, Raffles says, "Bóro is the name of the district, and bódo means ancient." Most candi are named after a nearby village. If it followed Javanese language conventions and was named after the nearby village of Bore, the monument should have been named "BudurBoro". Soekmono says Raffles thought that Budur might correspond to the modern Javanese word Buda ("ancient")—i.e., "ancient Boro". He also suggested that the name might derive from boro, meaning "great" or "honorable" and Budur for Buddha. However, another archaeologist suggests the second component of the name (Budur) comes from Javanese term bhudhara ("mountain").

Another possible etymology by Dutch archaeologist A.J. Bernet Kempers suggests that Borobudur is a corrupted simplified local Javanese pronunciation of Biara Beduhur written in Sanskrit as Vihara Buddha Uhr. The term Buddha-Uhr could mean "the city of Buddhas", while another possible term Beduhur is probably an Old Javanese term, still surviving today in Balinese vocabulary, which means "a high place", constructed from the stem word dhuhur or luhur (high). This suggests that Borobudur means vihara of Buddha located on a high place or on a hill.

The construction and inauguration of a sacred Buddhist building—possibly a reference to Borobudur—was mentioned in two inscriptions, both discovered in Kedu, Temanggung Regency. The Karangtengah inscription, dated 824, mentioned a sacred building named Jinalaya (the realm of those who have conquered worldly desire and reached enlightenment), inaugurated by Pramodhawardhani, daughter of Samaratungga. The Tri Tepusan inscription, dated 842, is mentioned in the sima, the (tax-free) lands awarded by Çrī Kahulunnan (Pramodhawardhani) to ensure the funding and maintenance of a Kamūlān called Bhūmisambhāra. Kamūlān is from the word mula, which means "the place of origin", a sacred building to honor the ancestors, probably those of the Sailendras. Johannes Gijsbertus de Casparis suggested that Bhūmi Sambhāra Bhudhāra, Sanskrit for a mountain of combined virtues after the ten stages of Boddhisattvahood, was the original name of Borobudur.

Approximately 40 kilometres (25 mi) northwest of Yogyakarta and 86 kilometres (53 mi) west of Surakarta, Borobudur is located in an elevated area between twin volcanoes, Sundoro-Sumbing and Merbabu-Merapi, and two rivers, the Progo and the Elo. According to local myth, the area known as Kedu Plain is a Javanese "sacred" place and has been dubbed "the garden of Java" due to its high agricultural fertility.

During the restoration in the early 20th century, Theodoor van Erp [nl] discovered that three Buddhist temples in the region, Borobudur, Pawon and Mendut, are positioned along a straight line. A ritual relationship between the three temples must have existed, although the exact ritual process is unknown.

Speculation about a surrounding lake's existence was the subject of intense discussion among archaeologists in the 20th century, and while the idea was explored, experts concluded that a lake was not present or never surrounded the temple. Advancing the lake hypothesis in 1931, Dutch painter W.O.J. Nieuwenkamp thought Borobudur represented a lotus flower floating on a lake in what is now the Kedu Plain. In 2004, others claimed that Borobudur was built above the floor of a dried-out paleolake. Examining samples from excavations in 1974 and 1977, Ganapathi Thanikaimoni could not find any pollen or spores that would indicate vegetation endemic to a water environment; Jacques Dumarçay published this work in 1977, as did Thanikaimoni in 1983. Caesar Voûte and J.J. Nossin made field studies in 1985–86 that confirmed the absence of a lake around Borobudur when it was built.

Hindu clerics appealed to the people of Java for generations, a fact that architect and author Jacques Dumarçay finds first mentioned in 450 AD. Influence of the Sailendra and Sanjaya dynasties followed. Dumarçay says that de Casparis concluded that Sanjaya and Sailendra shared power in central Java for a century and a half, and that de Casparis traced alternating succession from 732 until 882. During this time many Hindu and Buddhist monuments were built on the plains and mountains around the Kedu Plain. Buddhist monuments, including Borobudur, were erected around the same period as the Hindu Prambanan temple compound. In 732 AD, King Sanjaya commissioned a Shivalinga sanctuary to be built on the Wukir hill, only 10 km (6.2 mi) east of Borobudur.

There are no known records of construction or the intended purpose of Borobudur. The duration of construction has been estimated by comparison of carved reliefs on the temple's hidden foot and the inscriptions commonly used in royal charters during the 8th and 9th centuries. Comparison of an Indian architectural process across temples, and acknowledgment of who was in power, enabled Dumarçay to approximately date the construction of Borobudur in five stages. Loosely, the Sailendra began c. 780, and continued stages two and three c. 792 through to an unremarkable fourth stage during their decline c. 824. The Sanjaya completed Borobudur's fifth stage c. 833.

Construction of Buddhist temples, including Borobudur, at that time was possible because Sanjaya's immediate successor, Rakai Panangkaran, granted his permission to the Buddhist followers to build such temples. In fact, to show his respect, Panangkaran gave the village of Kalasan to the Buddhist community, as is written in the Kalasan Charter dated 779 AD. This has led some archaeologists to believe that there was never serious conflict concerning religion in Java as it was possible for a Hindu king to patronize the establishment of a Buddhist monument; or for a Buddhist king to act likewise. The 856 battle on the Ratubaka plateau was much after and was a political battle. There was a climate of peaceful coexistence where Sailendra involvement existed in Prambanan.

Borobudur lay hidden for centuries under layers of volcanic ash and jungle growth. The facts behind its abandonment remain a mystery. It is not known when active use of the monument and Buddhist pilgrimage to it ceased. Sometime between 928 and 1006, King Mpu Sindok moved the capital of the Mataram Kingdom to the region of East Java after a series of volcanic eruptions; it is not certain whether this influenced the abandonment, but several sources mention this as the most likely period of abandonment. The monument is mentioned vaguely as late as c. 1365, in Mpu Prapanca's Nagarakretagama, written during the Majapahit era and mentioning "the vihara in Budur".

Raden Soekmono mentioned the assumption of the temple abandonment, which occurred after the population had converted to Islam in the 15th century. The monument was not forgotten completely, and folk stories gradually became superstitious beliefs associated with bad luck and misery, which Soekmono relates. According to the Babad Tanah Jawi (or the History of Java), the monument was a fatal factor for a rebel who revolted against the king of Mataram in 1709. The insurgent was defeated and sentenced to death. In the Babad Mataram (or the History of the Mataram Kingdom), the monument was associated with the misfortune of the crown prince of the Yogyakarta Sultanate in 1757. In spite of a taboo against visiting the monument, the prince "took such pity on 'the knight who was captured in a cage' (i.e. the statue in one of the perforated stupas) that he could not help coming to see his 'unfortunate friend'". Upon returning to his palace, the prince fell ill and died one day later.

Following its capture, Java was under British administration from 1811 to 1816. Britain's representative and governor-general was Stamford Raffles, who took great interest in the history of Java. He collected Javanese antiques and made notes through contacts with local inhabitants during his tour throughout the island. On an inspection tour to Semarang in 1814, he was informed about a big monument deep in a jungle near the village of Bumisegoro. He sent Hermann Cornelius [nl], a Dutch engineer who, among other antiquity explorations had uncovered the Sewu complex in 1806–07, to investigate. In two months, Cornelius and his 200 men cut down trees, burned down vegetation and dug away the earth to reveal the monument. Due to the danger of collapse, he could not unearth all galleries. Cornelius reported his findings to Raffles, including various drawings. Although Raffles mentioned the discovery in only a few sentences in his book, and did not visit the site himself, he has been credited with the monument's rediscovery, as the one who had brought it to the world's attention.

Christiaan Lodewijk Hartmann, the resident of the Kedu region, continued Cornelius's work, and in 1835, the whole complex was finally unearthed. His interest in Borobudur was more personal than official. Hartmann did not write any reports of his activities, in particular, the alleged story that he discovered the large statue of Buddha in the main stupa. In 1842, Hartmann investigated the main dome, although what he discovered is unknown and the main stupa remains empty.

The Dutch East Indies government then commissioned Frans Carel Wilsen, a Dutch engineering official, who studied the monument and drew hundreds of relief sketches. Jan Frederik Gerrit Brumund was also appointed to make a detailed study of the monument, which was completed in 1859. The government intended to publish an article based on Brumund's study supplemented by Wilsen's drawings, but Brumund refused to cooperate. The government then commissioned another scholar, Conradus Leemans, who compiled a monograph based on Brumund's and Wilsen's sources. In 1873, the first monograph of the detailed study of Borobudur was published, followed by its French translation a year later. The first photograph of the monument was taken in 1872 by the Dutch-Flemish engraver Isidore van Kinsbergen.

In 1882, the chief inspector of cultural artifacts recommended that Borobudur be entirely disassembled with the relocation of reliefs into museums due to the unstable condition of the monument. As a result, the government appointed Willem Pieter Groeneveldt, curator of the archaeological collection of the Batavian Society of Arts and Sciences, to undertake a thorough investigation of the site and to assess the actual condition of the complex; his report found that these fears were unjustified and recommended it be left intact.

Borobudur was considered as the source of souvenirs, and parts of its sculptures were looted, some even with colonial-government consent. In 1896 King Chulalongkorn of Siam visited Java and requested and was allowed to take home eight cartloads of sculptures taken from Borobudur. These include thirty pieces taken from a number of relief panels, five buddha images, two lions, one gargoyle, several kala motifs from the stairs and gateways, and a guardian statue (dvarapala). Several of these artifacts, most notably the lions, dvarapala, kala, makara and giant waterspouts are now on display in the Java Art room in The National Museum in Bangkok.

Borobudur attracted attention in 1885, when the Dutch engineer Jan Willem IJzerman [id; nl], chairman of the Archaeological Society in Yogyakarta, discovered that the temple base enclosed a hidden foot. Photographs made in 1890–1891 revealed reliefs on the hidden foot; the coverings were then replaced. The discovery led the Dutch East Indies government to take steps to safeguard the monument. In 1900, a three-member commission formed to plan protection, and in 1902, the commission submitted a threefold proposal. First, collapse could be avoided by resetting the corners, removing stones that endangered the adjacent parts, strengthening the first balustrades and restoring several niches, archways, stupas and the main dome. Second, care should be maintained and water discharge should be improved by restoring floors and spouts. Third, all loose stones should be removed, the monument cleared up to the first balustrades, disfigured stones removed and the main dome restored. In 1905, the proposal was approved, and the total cost was estimated at that time around 48,800 Dutch guilders (equivalent to ƒ1,392,279 in 2022).

The restoration began in 1907, led by Theodoor van Erp [nl], a Dutch army engineer. The first seven months of restoration were occupied with excavating the grounds around the monument to find missing Buddha heads and panel stones. Van Erp dismantled and rebuilt the upper three circular platforms and stupas. Along the way, van Erp discovered more things he could do to improve the monument; he submitted another proposal in 1908, which was approved with the additional budget of 34,600 guilders (equivalent to ƒ875,176 in 2022). The restoration was completed in 1911 and at first glance, Borobudur had been restored to its old glory. Van Erp went further by carefully reconstructing the chattra (three-tiered parasol) pinnacle on top of the main stupa. However, he later dismantled the chattra, citing that there were not enough original stones used in reconstructing the pinnacle, which means that the original design of Borobudur's pinnacle is actually unknown. The dismantled chattra now is stored in Karmawibhangga Museum, a few hundred meters north from Borobudur.

Due to the limited budget, the restoration had been primarily focused on cleaning the sculptures, and van Erp did not solve the drainage problem. Within fifteen years, the gallery walls were sagging, and the reliefs showed signs of new cracks and deterioration. Van Erp used concrete from which alkali salts and calcium hydroxide leached and were transported into the rest of the construction. This caused some problems, so that a further thorough renovation was urgently needed.

Small restorations had been performed since then, but not sufficient for complete protection. During World War II and Indonesian National Revolution in 1945 to 1949, Borobudur restoration efforts were halted. The monument suffered further from the weather and drainage problems, which caused the earth core inside the temple to expand, pushing the stone structure and tilting the walls. By 1950s some parts of Borobudur were facing imminent danger of collapsing. In 1965, Indonesia asked the UNESCO for advice on ways to counteract the problem of weathering at Borobudur and other monuments. In 1968, Soekmono, then head of the Archeological Service of Indonesia, launched his "Save Borobudur" campaign, in an effort to organize a massive restoration project.

In the late 1960s, the Indonesian government had requested from the international community a major renovation to protect the monument. In 1973, a master plan to restore Borobudur was created. Through an Agreement concerning the Voluntary Contributions to be Given for the Execution of the Project to Preserve Borobudur (Paris, 29 January 1973), Australia, Belgium, Cyprus, France and Germany agreed to contribute to the restoration. The Indonesian government and UNESCO then undertook the complete overhaul of the monument in a big restoration project between 1975 and 1982.

In 1975, the actual work began. Over one million stones were dismantled and removed during the restoration, and set aside like pieces of a massive jig-saw puzzle to be individually identified, catalogued, cleaned and treated for preservation. Borobudur became a testing ground for new conservation techniques, including new procedures to battle the microorganisms attacking the stone. The attempt was made to restore the structure as much as possible using reassembled original materials (anastylosis method), with new andesite stone blocks used sparingly to replaces some missing stones, only to ensure structural integrity. The foundation was stabilized, and all 1,460 panels were cleaned. The restoration involved the dismantling of the five square platforms and the improvement of drainage by embedding water channels into the monument. Both impermeable and filter layers were added. This colossal project involved around 600 people to restore the monument and cost a total of US$6,901,243 (equivalent to US$47,367,152 in 2023).

After the renovation was finished, UNESCO listed Borobudur as a World Heritage Site in 1991. It is listed under Cultural criteria (i) "to represent a masterpiece of human creative genius", (ii) "to exhibit an important interchange of human values, over a span of time or within a cultural area of the world, on developments in architecture or technology, monumental arts, town-planning or landscape design", and (vi) "to be directly or tangibly associated with events or living traditions, with ideas, or with beliefs, with artistic and literary works of outstanding universal significance".

In December 2017, the idea to reinstall chattra on top of Borobudur main stupa's yasthi has been revisited. However, an expert said a thorough study is needed on restoring the umbrella-shaped pinnacle. By early 2018, the chattra restoration has not yet commenced.

Following the major 1973 renovation funded by UNESCO, Borobudur is once again used as a place of worship and pilgrimage. Once a year, during the full moon in May or June, Buddhists in Indonesia observe Vesak (Indonesian: Waisak) day commemorating the birth, death, and the time when Siddhārtha Gautama attained the perfect enlightenment to become the Buddha. Waisak is an official national holiday in Indonesia, and the ceremony is centered at the three Buddhist temples by walking from Mendut to Pawon and ending at Borobudur.

The rituals held in Borobudur including Pradakshina or circumabulating Borobudur clockwise while also ascending the stages of Borobudur through the galleries, meditation surrounding Borobudur, and might also include the release of sky lanterns.

The monument is the single most visited tourist attraction in Indonesia. In 1974, 260,000 tourists visited the monument; 36,000 of them were foreigners. The figure climbed to 2.5 million visitors annually (80% were domestic tourists) in the mid-1990s, before the country's economic crisis. Tourism development, however, has been criticized for not including the local community, giving rise to occasional conflicts. In 2003, residents and small businesses around Borobudur organized several meetings and poetry protests, objecting to a provincial government plan to build a three-storey mall complex, dubbed "Java World".

In June 2012, Borobudur was recorded in the Guinness Book of World Records as the world's largest Buddhist temple.

UNESCO identified three specific areas of concern under the present state of conservation: (i) vandalism by visitors; (ii) soil erosion in the south-eastern part of the site; and (iii) analysis and restoration of missing elements. The soft soil, the numerous earthquakes and heavy rains lead to the destabilization of the structure. Earthquakes are by far the most important contributing factors, since not only do stones fall down and arches crumble, but the earth itself can move in waves, further destroying the structure. The increasing popularity of the stupa brings in many visitors, most of whom are from Indonesia. Despite warning signs on all levels not to touch anything, the regular transmission of warnings over loudspeakers and the presence of guards, vandalism on reliefs and statues is a common occurrence and problem, leading to further deterioration.

Borobudur was heavily affected by the eruption of Mount Merapi in October and November 2010. Volcanic ash from Merapi fell on the temple complex, which is approximately 28 kilometres (17 mi) west-southwest of the crater. A layer of ash up to 2.5 centimetres (1 in) thick fell on the temple statues during the eruption of 3–5 November, covering the reliefs and clogging the drainage-system, with experts fearing that the acidic ash might damage the historic site. The temple complex was closed from 5 to 9 November to clean up the ashfall.

UNESCO donated US$3 million (equivalent to US$4,063,314 in 2023) as a part of the costs towards the rehabilitation of Borobudur after Mount Merapi's 2010 eruption. More than 55,000 stone blocks comprising the temple's structure were dismantled to restore the drainage system, which had been clogged by slurry after the rain. The restoration was finished in November.

In January 2012, two German stone-conservation experts spent ten days at the site analyzing the temples and making recommendations to ensure their long-term preservation. In June, Germany agreed to contribute US$130,000 (equivalent to US$172,529 in 2023) to UNESCO for the second phase of rehabilitation, in which six experts in stone conservation, microbiology, structural engineering and chemical engineering would spend a week in Borobudur in June, then return for another visit in September or October. These missions would launch the preservation activities recommended in the January report and would include capacity building activities to enhance the preservation capabilities of governmental staff and young conservation experts.

On 14 February 2014, major tourist attractions in Yogyakarta and Central Java, including Borobudur, Prambanan and Ratu Boko, were closed to visitors, after being severely affected by the volcanic ash from the eruption of Kelud volcano in East Java, located around 200 kilometers east from Yogyakarta. Workers covered the iconic stupas and statues of Borobudur temple to protect the structure from volcanic ash. The Kelud volcano erupted on 13 February 2014 with an explosion heard as far away as Yogyakarta.

On 21 January 1985, nine stupas were badly damaged by nine bombs. In 1991, a blind Muslim preacher, Husein Ali Al Habsyie, was sentenced to life imprisonment for masterminding a series of bombings in the mid-1980s, including the temple attack. Two other members of the Islamic extremist group that carried out the bombings were each sentenced to 20 years in 1986, and another man received a 13-year prison term.

On 27 May 2006, an earthquake of 6.2 magnitude struck the south coast of Central Java. The event caused severe damage around the region and casualties to the nearby city of Yogyakarta and Prambanan, but Borobudur remained intact.

In August 2014, Indonesian police and security forces tightened the security in and around Borobudur temple compound, as a precaution to a threat posted on social media by a self-proclaimed Indonesian branch of ISIS, citing that the terrorists planned to destroy Borobudur and other statues in Indonesia. The security improvements included the repair and increased deployment of CCTV monitors and the implementation of a night patrol in and around the temple compound. The jihadist group follows a strict interpretation of Islam that condemns any anthropomorphic representations such as sculptures as idolatry.

The high volume of visitors ascending the Borobudur's narrow stairs, has caused a severe wear out on the stone of the stairs, eroding the stones surface and made them thinner and smoother. Overall, Borobudur has 2,033 surfaces of stone stairs, spread over four cardinal directions; including the west side, the east, south and north. There are around 1,028 surfaces of them, or about 49.15 percent, that are severely worn out.

To avoid further wear of stairs' stones, since November 2014, two main sections of Borobudur stairs – the eastern (ascending route) and northern (descending route) sides – are covered with wooden structures. A similar method has been used in Angkor Wat in Cambodia and Egyptian Pyramids. In March 2015, Borobudur Conservation Center proposed further to seal the stairs with rubber cover.

Due to vandalism and graffiti, access to the temple grounds was temporarily blocked in 2020. Since then, a maximum of 1200 visitors are allowed to enter the temple for one hour a day accompanied by tourist guides. Visitors are expected to wear bamboo slippers.

According to Statistics Indonesia, the number of domestic tourists rose from 422,930 in 2021 to 1.44 million in 2022. The Indonesian government is aiming to increase the number of tourists to 2 million per year.

The archaeological excavation into Borobudur during reconstruction suggests that adherents of Hinduism or a pre-Indic faith had already begun to erect a large structure on Borobudur's hill before the site was appropriated by Buddhists. The foundations are unlike any Hindu or Buddhist shrine structures, and therefore, the initial structure is considered more indigenous Javanese than Hindu or Buddhist.

Borobudur is built as a single large stupa and, when viewed from above, takes the form of a giant tantric Buddhist mandala, simultaneously representing the Buddhist cosmology and the nature of mind. Some scholars reject the idea that it is a mandala because, in their view, no evidence is present to suggest that the Shailendras were followers of Tantric or Vajrayana Buddhism. Moreover, the Buddhas of the Borobudur do not identify as the Five Tathagatas. The original foundation is a square, approximately 118 metres (387 ft) on each side. It has nine platforms, of which the lower six are square and the upper three are circular. The upper platform contains seventy-two small stupas surrounding one large central stupa. Each stupa is bell-shaped and pierced by numerous decorative openings. Statues of the Buddha sit inside the pierced enclosures.

The design of Borobudur took the form of a step pyramid. Previously, the prehistoric Austronesian megalithic culture in Indonesia had constructed several earth mounds and stone step pyramid structures called punden berundak as discovered in Pangguyangan site near Cisolok and in Cipari near Kuningan. The construction of stone pyramids is based on native beliefs that mountains and high places are the abode of ancestral spirits or hyangs.

The monument's three divisions symbolize the three "realms" of Buddhist cosmology, namely Kamadhatu (the world of desires), Rupadhatu (the world of forms), and finally Arupadhatu (the formless world). Ordinary sentient beings live out their lives on the lowest level, the realm of desire. Those who have burnt out all desire for continued existence leave the world of desire and live in the world on the level of form alone: they see forms but are not drawn to them. Finally, full Buddhas go beyond even form and experience reality at its purest, most fundamental level, the formless ocean of nirvāṇa. The liberation from the cycle of saṃsāra where the enlightened seeker is no longer attached to worldly form corresponds to the concept of sūnyatā, the complete voidness or the nonexistence of the self. Kāmadhātu is represented by the base, Rupadhatu by the five square platforms (the body), and Arupadhatu by the three circular platforms and the large topmost stupa. The architectural features between the three stages have metaphorical differences. For instance, square and detailed decorations in the Rupadhatu disappear into plain circular platforms in the Arupadhatu to represent how the world of forms—where men are still attached with forms and names—changes into the world of the formless.

Congregational worship in Borobudur is performed in a walking pilgrimage. Pilgrims are guided by the system of staircases and corridors ascending to the top platform. Each platform represents one stage of enlightenment. The path that guides pilgrims was designed to symbolize Buddhist cosmology.

In 1885, a hidden structure under the base was accidentally discovered. The "hidden footing" contains reliefs, 160 of which depict narratives describing the world of desires. The remaining reliefs are panels with short inscriptions that apparently provide instructions for the sculptors, illustrating the scenes to be carved. The real base is hidden by an encasement base, the purpose of which remains a mystery. It was first thought that the real base had to be covered to prevent a disastrous subsidence of the monument into the hill. There is another theory that the encasement base was added because the original hidden footing was incorrectly designed, according to Vastu Shastra, the Indian ancient book about architecture and town planning. Regardless of why it was commissioned, the encasement base was built with detailed and meticulous design and with aesthetic and religious consideration.

There are quite a few design similarities between the Borobudur and Kesaria sites. Both sites have mandalas and life like Buddhas facing the sections of the universe. Both sites have hill-like mandala structures filled with Buddhist statues. This hints at the travel of ritualistic texts and ideas between the Pala and Srivijaya domains.

Approximately 55,000 cubic metres (72,000 cu yd) of andesite stones were taken from neighbouring stone quarries or from the bed of the Progo River to build the monument. The stone was cut to size, transported to the site and laid without mortar. Knobs, indentations and dovetails were used to form joints between stones. The roof of stupas, niches and arched gateways were constructed in corbelling method. Reliefs were created in situ after the building had been completed.

The monument is equipped with a good drainage system to cater to the area's high stormwater run-off. To prevent flooding, 100 spouts are installed at the corners, each with a unique carved gargoyle in the shape of a giant or makara.

Borobudur differs markedly from the general design of other structures built for this purpose. Instead of being built on a flat surface, Borobudur is built on a natural hill. However, construction technique is similar to other temples in Java. Without the inner spaces seen in other temples, and with a general design similar to the shape of pyramid, Borobudur was first thought more likely to have served as a stupa, instead of a temple. A stupa is intended as a shrine for the Buddha. Sometimes stupas were built only as devotional symbols of Buddhism. A temple, on the other hand, is used as a house of worship. The meticulous complexity of the monument's design suggests that Borobudur is in fact a temple.

Little is known about Gunadharma, the architect of the complex. His name is recounted from Javanese folk tales rather than from written inscriptions.